In various scenarios, like for example illumination of small areas (for example for displaying of pixels for displaying information) or large areas (for example for illuminating a wall with effects for the spectators' amusement), conversion of light from one color to another color may be desired.
US2009284148 A1 discloses a projector which uses a light source unit that has a plurality of fan-shaped segment areas on a circular transparent base material which can be controlled to rotate. Layers of different phosphors which emit light of predetermined wavelength bands by receiving excitation light from an excitation light source are disposed on at least two of the segment areas on the transparent base material.